1. Field of the Invention
The present invention relates to closure means for structural members such as doors, windows, truck beds and the like and, more specifically, it relates to such an assembly which is easy to install and may sustain impact loads with minimum structural damage.
2. Description of the Prior Art
It has been known for numerous structural usages to provide various forms of movable closures such as doors and windows, for example, including those which may be subjected to frequent use and abuse as in an industrial or commercial environment.
It has also been known to provide such doors with closure members made of flexible materials which may be received on and released from a motorized reel so as to open and close the doors. One of the problems with industrial doors of this type is that they are frequently subjected to undesired high impact loads which do structural damage to the door, the door frames, or both.
U.S. Pat. No. 550,412 discloses a means for clamping and unclamping screen material between framing members by employing pins which slide in angularly disposed slots moving in a plane generally perpendicular to the plane of the screen material. U.S. Pat. No. 1,961,383 discloses window screens having pins moving in angularly disposed slots which serve as stop members.
A clamping mechanism for a window screen is disclosed in U.S. Pat. No. 1,892,001.
U.S. Pat. No. 2,886,103 discloses a retractable system for windows wherein a cam slot serves to provide clamping once the closure is in place.
U.S. Pat. No. 2,594,910 discloses a roll-up type cover for trucks and trailers. U.S. Pat. No. 2,584,014 discloses a removable truck top.
U.S. Pat. No. 4,649,981 discloses a shade with a flap cut out of the shade material and reintroduced thereto when the shade is rolled up, apparently, to eliminate excess size build-up in the rolled material.
A window screen having projecting tabs which are adapted to move in a slot is disclosed in U.S. Pat. No. 618,831. U.S. Pat. No. 1,425,484 also discloses a screen member having portions which ride in a track.
U.S. Pat. No. 1,673,326 discloses a spring biased tensioning mount for applying tension to a screen.
U.S. Pat. No. 1,387,452 discloses a window screen having a roller cam which may be rotated by means of an operating handle in order to cam the screen fabric against the track wall.
In spite of these previously known systems, there remains a need for an improved closure system for structural members which will resist undesired damage, provide effective sealing, and function in an efficient manner under a wide variety of operating conditions.